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Considering the high demand for innovative solutions in medicine, a major increase in interest in biomaterials research has been noticed, with the most significant advancements in metals and their alloys. Titanium-based alloys are one of the most recognised in the scientific community but do not represent the only way to achieve optimal results. Zirconium alloys for medical applications are a novelty with significant research potential based on their outstanding properties, which may be of value for medicine. The aim of the present study was to obtain new biomedical Zr-Nb-Mo alloys with varying ratios of their respective elements—Zr and Mo—using combined powder metallurgy (PM) and arc melting (VAM) methods. The obtained samples underwent microstructure analysis using an optical microscope (OM) and a scanning electron microscope (SEM). The study of element distribution was conducted with energy dispersive spectroscopy (EDS), whereas the phase composition was determined using X-ray diffraction (XRD). Mechanical properties were examined with a Micro Combi Tester MCT3, whereas tribological properties were assessed with a TRN Tribometer, and Ringer's solution was used as a lubricant. Additionally, the wear tracks of the studied samples were observed using the SEM. The research results indicated that increased Mo content conduced to microstructure refinement and homogeneity. Furthermore, the higher content of this element contributed to the growth of the HVIT, HIT, and EIT parameters, together with the improvement in the tribological performance of the alloys. XRD analysis revealed that the obtained samples were multiphase, and raising the Mo addition promoted the formation of new phases, including a ternary phase—Zr0.9Nb0.66Mo1.44 (Fd 3 ¯ m). The chemical composition study showed uneven distribution of niobium and areas of uneven mutual distribution of zirconium and molybdenum. [ABSTRACT FROM AUTHOR]

Medicine is looking for solutions to help implant patients recover more smoothly. The porous implants promote osteointegration, thereby providing better stabilization. Introducing porosity into metallic implants enhances their biocompatibility and facilitates osteointegration. The introduction of porosity is also associated with a reduction in Young's modulus, which reduces the risk of tissue outgrowth around the implant. However, the risk of chronic inflammation remains a concern, necessitating the development of coatings to mitigate adverse reactions. An interesting biomaterial for such modifications is chitosan, which has antimicrobial, antifungal, and osteointegration properties. In the present work, a porous titanium biomaterial was obtained by powder metallurgy, and electrophoretic deposition of chitosan coatings was used to modify its surface. This study investigated the influence of ethanol content in the deposition solution on the quality of chitosan coatings. The EPD process facilitates the control of coating thickness and morphology, with higher voltages resulting in thicker coatings and increased pore formation. Ethanol concentration in the solution affects coating quality, with higher concentrations leading to cracking and peeling. Optimal coating conditions (30 min/10 V) yield high-quality coatings, demonstrating excellent cell viability and negligible cytotoxicity. The GIXD and ATR-FTIR analysis confirmed the presence of deposited chitosan coatings on Ti substrates. The microstructure of the chitosan coatings was examined by scanning electron microscopy. Biological tests showed no cytotoxicity of the obtained materials, which allows for further research and the possibility of their use in medicine. In conclusion, EPD offers a viable method for producing chitosan-based coatings with controlled properties for biomedical applications, ensuring enhanced patient outcomes and implant performance. [ABSTRACT FROM AUTHOR]

The microstructures and structures of modified Al2O3/IF-WS2 coatings prepared on aluminum substrates are studied. Amorphous Al2O3 oxide coatings are obtained on EN AW 5251 aluminum alloy using the electrooxidation process. The quality of the IF-WS2 nanopowder is of great importance in the process of its introduction into the nanopores of the Al2O3 oxide coating. Commercial nanopowder tends to agglomerate, and without appropriate pretreatment, it is difficult to introduce it into the nanopores of the coating. To improve the degree of fragmentation of the IF-WS2 nanopowder, an experiment was carried out to distribute the nanopowder in the presence of strong ultrasounds, and new conditions for introducing the powder into the nanopores were used. A two-level design of experiment (DOE) was used. The SEM examination made it possible to conclude that Method A contributed to a more even distribution of nanoparticles in the microstructure of Al2O3 coatings. GIXD analyses showed the presence of WO3 derived from the IF-WS2 modifier next to crystal structures derived from aluminum and WS2. Modification of coatings using Method A resulted in surfaces with lower contact angles measured with polar liquids and higher surface free energy compared to Method B. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to learn the morphological, structural, ferroelectric, dielectric, electromechanical, magnetoelectric, and magnetic properties, and DC conductivity of BaTiO3-Ni0.64Zn0.36Fe2O4 (BT-F) multiferroic composites compacted via the free sintering method. The influence of the ferrite content in ceramic composite materials on the functional properties is investigated and discussed. X-ray diffraction studies confirmed the presence of two main phases of the composite, with strong reflections originating from BaTiO3 and weak peaks originating from nickel-zinc ferrite. BT-F ceramic composites have been shown to exhibit multiferroism at room temperature. All studied compositions have high permittivity values and low dielectric loss, while the ferroelectric properties of the BT component are maintained at a high level. On the other hand, magnetic properties depend on the amount of the ferrite phase and are the strongest for the composition with 15 wt.% of F (magnetization at RT is 4.12 emu/g). The magnetoelectric coupling between BT and F phases confirmed by the lock-in technique is the largest for 15 wt.% ferrite. In the present work, the process conditions of the free sintering method for obtaining BT-F multiferroic composite with good electrical and magnetic properties (in one material) were optimized. An improved set of multifunctional properties allows the expansion of the possibilities of using multiferroic composites in microelectronics. [ABSTRACT FROM AUTHOR]

Using the free (pressureless) sintering method, multiferroic ceramic composites based on two ferroelectric materials, i.e., BaTiO3 (B) and Pb0.94Sr0.06 (Zr0.46Ti0.54)0.99Cr0.01O3 (P), and magnetic material, i.e., zinc–nickel ferrite (F) were obtained. Three composite compositions (BP-F) were obtained with a constant 90/10 content (ferroelectric/magnetic) and a variable content of the ferroelectric component (B/P), i.e., 70/30, 50/50, and 30/70. Crystalline structure, microstructural, DC electrical conductivity, dielectric, and ferroelectric properties of multiferroic composites were investigated. The concept of a composite consisting of two ferroelectric components ensures the preservation of sufficiently high ferroelectric properties of multiferroic composites sintered by the free sintering method. Research has shown that the percentage of individual ferroelectric components in the composite significantly affects the functional properties and the entire set of physical parameters of the multiferroic BP-F composite. In the case of the dielectric parameters, the best results were obtained for the composition with a more significant amount of BaTiO3; i.e., permittivity is 1265, spontaneous polarization is 7.90 µC/cm2, and remnant polarization is 5.40 µC/cm2. However, the most advantageous set of performance parameters shows the composite composition of 50BP-F. [ABSTRACT FROM AUTHOR]

This paper examines the optimal aging temperature of WE43 alloy that has undergone precipitation hardening in conjunction with deep cryogenic treatment. The microstructure and phase composition were investigated, a microanalysis of the chemical composition was performed, and instrumental indentation tests were performed to determine the parameters of the micro-mechanical properties of the alloy after different heat treatment variants. It has been proven that a decrease in the aging temperature from 250 °C to 225 °C and the introduction of a deep cryogenic treatment lead to favorable changes in the microstructure of the alloy (reduction in grain size, increase in the number, and change in the type of β-phase precipitates). The changes in the alloy structure achieved by lowering the aging temperature contribute to the improvement of the micromechanical properties of the test material. The most advantageous results were recorded for an alloy subjected to solution treatment and aged at 225 °C for 24 h with deep cryogenic treatment: a 30% increase in hardness, a 10% increase in Young's modulus, an improvement in elastic properties, and increased resistance to deformation of the alloy were shown compared to the initial (as-received) state. Raising the aging temperature to 250 °C leads to a phenomenon known as alloy overaging for both alloys after classical precipitation hardening and after deep cryogenic treatment. The results indicate the significant effectiveness of the proposed heat treatment in improving the service life of the Mg-Y-Nd-Zr (WE43) alloy. [ABSTRACT FROM AUTHOR]

The paper introduces spatially stable Ni-supported bimetallic catalysts for CO2 methanation. The catalysts are a combination of sintered nickel mesh or wool fibers and nanometal particles, such as Au, Pd, Re, or Ru. The preparation involves the nickel wool or mesh forming and sintering into a stable shape and then impregnating them with metal nanoparticles generated by a silica matrix digestion method. This procedure can be scaled up for commercial use. The catalyst candidates were analyzed using SEM, XRD, and EDXRF and tested in a fixed-bed flow reactor. The best results were obtained with the Ru/Ni-wool combination, which yields nearly 100% conversion at 248 °C, with the onset of reaction at 186 °C. When we tested this catalyst under inductive heating, the highest conversion was observed already at 194 °C. [ABSTRACT FROM AUTHOR]